a mountain that forms when magma is forced onto Earth's surface
What is a volcano?
100
a form of pyroclastic material that can block out the sun
What is volcanic ash?
100
the plate boundaries surrounding the Pacific Ocean that contain 75% of the world's volcanoes
What is the Ring of Fire?
100
pebble-like bits of magma
What is lapilli?
100
magma that flows onto Earth's surface
What is lava?
200
a volcanic eruption producing lava
What is a nonexplosive eruption?
200
a volcano built from layers of pyroclastic material and lava
What is a composite volcano?
200
a deep crack that forms when tectonic plates seperate
What is a rift?
200
a form of pyroclastic material that forms when the gases in stiff magma expand rapidly and the walls of the gas bubbles explode into tiny glass-like slivers
What is volcanic ash?
200
lava so thick it barely creeps along the ground
What is blocky lava?
300
a volcanic eruption shooting pyroclastic material into the air
What is an explosive eruption?
300
a pit that forms when a magma chamber empties and its roof collapses
What is a caldera?
300
a place on Earth's surface, directly above columns of rising magma
What is a hot spot?
300
large blobs of magma that harden in air
What are volcanic bombs?
300
lava that has a slightly jagged surface
What is Aa?
400
the largest pieces of pyroclastic material
What are volcanic blocks?
400
a volcano with gently sloping sides that can cover a wide area
What is a shield volcano?
400
an instrument that measures changes in thde slope of a volcano
What is a tiltmeter?
400
the largest pieces of pyroclastic material
What are volcanic blocks?
400
lava that forms from underwater eruptions
What is pillow lava?
500
a basic building block of most minerals; thickens magma
What is silica?
500
a volcano with steep sides and a narrow base
What is a cinder cone volcano?
500
the movement of one tectonic plate under another
What is subduction?
500
rock fragments created by explosive volcanic eruptions
What is pyroclastic material?
500
lava that flows slowly, like wax dripping from a candle